Method for controlling the height of a pile of delivered sheets



Oct. 10, 1950 H. E. PEYREBRUNE 2,525,311

METHOD FOR CONTROLLING THE HEIGHT OF A FILE OF DELIVERED SHEETSFiled-Feb. 18. 1946 Patented a. 10, 1950 2,525,311

UNITED STATES PATENT. OFFICE METHOD FOR CONTROLLING THE HEIGHT OF A PILEOF DELIVERED SHEETS Henri E. Peyrebrune, River Forest, Ill., assignor,by mesne assignments, to The Miehle Printing Press & ManufacturingCompany, Chicago, 111., a corporation of Delaware Application February18, 1946, Serial No. 648,258

1 Claim. (Cl. 271-88) 1 This invention relates to the art of deliveringsheets of paper or the like from printing presses operating on largesheets and capable of producing printed sheets in excess of 6,000 perhour.

More specifically the invention pertains to a 5 tracting the feelersbecomes correspondingly denovel method of controlling the height of apile creased resulting in consequent difllculties for of deliveredsheets by means of an electronic maintaining proper adjustments of themechanidevice. cal parts involved.

Heretofore, it has been common practice in I have found furthermore thatby applyingany sheet delivering machinery, to automatically con- 1conventional mechanical pile height controlling trol the movement of asheet receiving member, means to the margin or elsewhere of a stack ofsuch as a delivery table, by means of mechanisheets in such suspended,i. e. floating condition, cal feeler devices which are intermittentlyapthe position of the individual sheets as they float plied to contactthe top edge of a more or less down becomes disturbed, and as a resultit is firmly stacked pile of delivered sheets to thereimpossible to trueup the sheets and obtain a by initiate motion of mechanism formaintainsmooth delivery pile in which the sheets are ing the top of thepile at a predetermined level. accurately aligned.

In machines which handle and deliver sheets For numerous and obviousreasons it is highly at speeds not exceeding 4000 sheets per hour,desirable and in many cases essential that the such conventional meansdo operate satisfac- 2o delivered sheets be stacked in accuratesupertorily because at these speeds a sheet, after havimposed relation.For example, much labor and ing been deposited by the sheet carrier ofthe detime is saved in label jobs where the pile of delivery means, cansoon flatten out on the stack livered printed sheets is transferred to apower of previously delivered sheets. In other words, paper cuttingmachine in order to cut out the inthe air which is trapped between eachindividual dividual labels. sheet as it floats down onto the stack afterhav- Another instance which demands accurate ing been released. h s plim to esc pe fr m stacking of delivered sheets occurs in multicolorbeneath a sheet so that the sheet can settle on printing where sheetsare run through a press the stack and flatten out before a successiveseveral times to receive consecutive impressions. sheet is released bythe delivery mechanism. Realizing these and other facts, the primaryConsequently a substantially firm and unyielding support along themargin of the pile is maintained unto which the mechanical pile heightcontrolling means may be applied, without disturbing the alignment ofsheets while they are floating down onto the previously stacked andaligned sheets.

This condition changes, however, when the above quoted rate ofdelivering sheets is increased to say 6-7 thousand sheets per hour,particularly so when large sheets of comparatively light stock areinvolved. At such increased speeds, a considerable number of sheetsafter having been released by the delivery mechanism, remain suspendedfor a comparatively long period before all of the air between them canescape beyond the margins of the sheets. Not only do the sheets build upa marked bulge over the middle portion of the delivered pile but theyalso present a fiulfed margin around all four sides and at the cornersof the sheets.

Mechanical feelers which operate by contacting the top edge of the pileof sheets must be applied and retracted quickly between each deliveredsheet in order to allow the sheets to deposit themselves unto the pileand come to rest in accurate alignment with the previously depositedsheets. By increasing the rate of delivering sheets, the time availablefor applying and reobject of my invention is to provide a novel method,including the use of electronic control means, whereby the statedrequirements may be accomplished without in any manner interfering withthe delivered sheets while they are floating down onto their support.

A further object of the invention is to include in this novel method thesteps of directing a beam of light across the top of a delivered bank offloating sheets and to actuate the pile height controlling mechanismupon complete interception of said beam by the uppermost one of a stillfloating bank of sheets delivered by the sheet conveyor.

Other objects of the invention will be apparent from the followingdescription and appended claim.

One preferred means whereby the basic principle of my novel method maybe accomplished is illustrated in the accompanying drawings in which:

Figure 1 is a diagrammatic illustration depicting the delivery end of aprinting press with which my invention is associated;

Figure 2 is a perspective view of the delivery pile, showing to aslightly exaggerated degree the bulge which builds up when large sheetsare delivered at speeds above 4000 sheets per hour; and

Figure 3 is a fractional elevation of the delivery pile taken from theleft of Figure l and illustrating the manner in which a photoelectricdevice and its associated source of light may be arranged to project abeam of light across the top of a delivered bank of floating sheets.

It will be understood that among the problems which my inventionaccomplishes, is that of keeping the highest point of the delivered pileof sheets sufllciently low to avoid interference with the sheet conveyorand with the oncoming sheet.

Referring now to Figure l of the drawings, l indicates in broken lines asheet carrying member such as a transfer reel or cylinder of a printingpress from which sheets carried thereby are transferred to an endlesssheet carrier il also depicted in broken lines and provided with sheetengaging grippers l2, l3, whereby the sheets are taken over and conveyedfrom the member i0 and deposited onto the sheet receiving table l4.Conventional sheet jogging devices or blades l5 are provided to operatein the usual manner for the purpose of accurately aligningthe deliveredsheets as they accumulate on the table M to form a stack. Some, or allof these jogger blades are imparted intermittent motion to and from thedelivered pile of sheets by mechanism well known in the art.

Preferably, and as indicated in Figure 1, the

Joggers l5 which are arranged along the front edge of the pile, areinclined so that the leading edge of the oncoming, bulged sheets will beengaged by them in order to align the sheets. This arrangement mightalso be applied with advantage to any or all of the other jogger bladesi5.

As is well known in the art, the table H is preferably supported byI-bearns l6, l1, which are suspended by means of link chains is and I9respectively, indicated in broken lines,'and which chains pass aroundchain pulleys and 21 mounted on a shaft 22 which may be supported in anyconvenient manner by bearings .23 and 24 arranged on the frame of thedelivery mechanism.

Any well known and convenient friction or clutch mechanism, not shown,may be employed to hold the shaft 22 against unintended rotation.

The conveyor or sheet carrier li includes a pair of endless deliverychains such as are widely used in sheet delivery mechanism of printingpresses and similar machinery. These chains are driven in any approvedmanner through the intermediary of chain sprockets, not shown, andarranged at each end of the conveyor in bearings denoted at 25 and 26respectively.

The means whereby the sheet receiving table it is lowered to therebymaintain the top of the delivery pile on the table at a substantiallyconstant elevation comprises a ratchet mechanism which includes aratchet wheel 21 and associated pawl 28, which latter is intermittentlyactuated to advance the ratchet wheel 21 and therewith rotate the shaft22. The pawl 28 is reciprocated by means of a connecting arm 29 pivotedto the pawl and to a crank pin provided on a gear 30. The latter has adriving connection with any operating part of the press to rotate itcontinually.

It will be understood that so long as the pawl v 28 remains inengagement with the ratchet wheel 4 21, the shaft 22 which carries thechain pulleys 20 and 2i will be rotated intermittently and thereby thetable ll will be lowered correspondingly. It is therefore necessary, inorder to maintain the top of the pile of sheets delivered onto the tableit at a substantially constantv elevation, to disengage the pawl "fromthe ratchet wheel 21 and therewith interrupt the lowering of the tableit until sufficient sheets have been deposited onto the delivery pile tonecessitate a further lowering of the table.

Heretofore this intermittent lowering of the sheet receiving table hasbeen controlled by such means as mechanical pile height detectingmechanism, ratchet set wheel and hand operated lowering mechanism, allwell known in the art and which were applied to the edge of a pile ofsheets in a manner that when a predetermined height of the pile wasbuilt up by the oncoming delivered sheets, the delivery table loweringmeans would be actuated.

As indicated herein, when sheets are delivered at a rate surpassing 4000sheets per hour, the air trapped between the individual sheets cannotescape correspondingly quick beyond the margin of the sheets, and as aconsequence a fluffy bank comprising a large number of floating sheetsdevelops. Furthermore, in the middle portion of such bank of floatingsheets a high bulge builds up, see Figure 2 in particular, which showsin perspective a bank of still floating and separated sheets and thehigh bulge which is being developed. I have found that under suchconditions the conventional mechanical means such as have heretoforebeen used for controlling the height of a pile of delivered sheetscannot be applied because they disturb the position of the sheets whilethey are floating down onto the pile of previously delivered and stackedsheets, and therefore it is impossible to obtain a neat and accuratelyaligned pile of sheets.

Because of this fact it becomes necessary to provide some means whichshall not disturb the position of the still floating individual sheetsand provision of photoelectric elements which can be applied veryconveniently and which have proven most reliable in operation.

In Figures 1 and 3 I have illustrated schematically a suitablephotoelectric device and manner of applying it to the delivery of aprinting press. This device includes a switch box 3i through whichelectric energy is furnished to the photoelectric cell 32 and to thelight projector 33.

My preferred arrangement of the cell 32 and projector 33 is such that abeam of light 34 is directed across the central portion of the bulge 35of a ban: of floating sheets and in a manner that when the bulge hasreached a predetermined height, see Figure 3, the beam 34 will becompletely intercepted.

If for any reason it is found desirable, a plurality of photoelectriccells and associated parts may be disposed over the entire top of a pileso as to operate in conjunction for the purpose of accomplishing theobjects of my invention.

As indicated herein the pawl 28 is held out of engagement with theratchet wheel 21 until it becomes necessary to again lower the table l4upon the pile of sheets thereon, i. e. the top of the bulge reaching apredetermined level. I propose to accomplish this by means of a solenoid36 which remains energized so long as the light beam 34 is notcompletely intercepted by the delivered sheets. Operatively associatedwith this solenoid is a connecting rod 31 which in turn is pivotallyattached to the pawl 28 and functions to hold the pawl out of engagementwith the ratchet 21 until the beam 34 becomes completely interceptedduring the acting stroke of the pawl.

This renders the solenoid inoperative, permitting the rod 31 to drop andthe pawl and ratchet mechanism 2830 to assume its function of rotatingthe shaft 22 to thereby lower the table 14 sufl'lciently to re-establisha completely or at least partially unintercepted beam of light acrossthe top of the bulge 35, whereby the solenoid again becomes energized todisengage the pawl 28 from the ratchet 21 and consequently retain thetable M in its lowered position.

I have found that the height of the bulge 35 varies, depending on theweight of stock and size of sheets to be handled. Therefore it isdesirable to provide some means whereby the photoelectric cell 32 andpreferably also the projector 33 may be adjusted up and down. This canbe accomplished by a simple device such as I have indicated in Figure 1and may include a threaded stem which extends through a bore provided ina bracket 4|. This bracket is formed with a slot to accommodate anadjusting nut 42 screwed onto said stem 40, so that by turning the nutthe photoelectric cell can be raised or lowered. A similar arrangementcould be provided for likewise adjusting the projector 33.

In order to illustrate how the sheets are deposited unto the deliverypile by the endless ,conveyor l I I have indicated in broken lines theposition of a sheet just after it has been released by the grippers l3and while the trailing edge of the sheet is still controlled by aconventional suction roller 43 or the like.

It is assumed that the sheets shown in Figure l are 01 average size, inwhich event the cell 32 and projector 33 are located at substantiallythe center between the ends of the sheets. When larger sheets arehandled then of course the suction roller 43 and associated parts willbe moved further back, as indicated in broken lines in Figure 1, andlikewise when smaller sheets than the average size are to be delivered,the roller 43 and associated part must be moved a corresponding distancetoward the front of the pile. I have found that by arranging thephotoelectric cell 32 and projector 33 off-center with relation to otherthan average size sheets, these elements will function equally wellwithout modifying their off-center position.

' While I have chosen to illustrate and describe one preferred meanswhereby the advantages of my invention may be realized, it will beunderstood that I may resort to any modification of elements andarrangements thereof without departing from the basic principle setforth herein and recited in the appended claim.

I claim:

In the method of delivering large sheets of light-weight paper at highspeeds from a sheet processing machine to an adjustable sheet support,comprising the steps of conveying the sheets from said machine to aposition immediately above said support, engaging the rear end of eachsheet by restraining means immediately prior to their release by theconveying means to tauten the sheets in the direction of their traveland to retard their forward movement, releasing said .sheets by saidconveying means to drop them onto said support, said sheets, because oftheir light weight and the rapid speed of delivery, having a tendency tobuild up a bulge in the center due to the air trapped thereunder as theydescend onto the support, directing a beam of light across the bulgeformed by still floating sheets, applying said beam in a direction whereit will be completely intercepted, at times, by the uppermost portion ofsaid bulge, as new sheets are being delivered, impinging said beam ontoan electronic control device, the complete interception of said beam bysaid bulge causing the operation of said control device to thereby lowersaid support until partial interception only of said beam, is againestablished, and finally positioning the settled sheets by jogging meansafter the air has escaped from thereunder.

HENRI E. PEYREBRUNE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

